Readers can help the great detective Batman and his sidekicks solve riddles, analyze evidence, look for clues, and spot solutions to mysteries before he logs them into his casebook.

The great detective Banana Fox is called back to duty to find a missing turtle. But the deeper he digs, the more he discovers, and it's worse than he thought! The Secret Sour Society is back, and they're mixing up a bunch of trouble. Can Banana Fox and his sidekick, Flashlight, put an end to the Secret Sour Society once and for all?

"Geronimo Stilton is granted a special interview with the great Sourishi, who lives in isolation and rarely gives interviews. To reach him, Geronimo and company must take the Rodent-Express, a steam engine that zigs and zags across perilous terrain and steep mountains. But, during the journey, Bugsy Wugsy mysteriously disappears! Can Geronimo crack the case before the end of the line?"--Provided by publisher.